There exists in the art a variety of pump designs and configurations. All pumps have a primary purpose of transferring fluid, some of which perform the task in an energy efficient manner. Positive displacement pumps provide fluid transfer but require certain preexisting conditions for proper operation. Operation of a positive displacement pump on low influent fluid pressure will cause cavitation which results in irreparable damage to pump vanes. Positive displacement pumps are beneficial in that they operate on any speed motor and thus are not dependent upon the rotations per minute of the pump. For this reason, the positive displacement pump can transfer fluid at any rate as long as there is sufficient influent pressure so as to prevent cavitation and the motor revolutions thereafter determine the amount of volume the pump will transfer.
Another well known type of pump is referred to as a centrifugal pump wherein a rotating vane with patterned orifice allows fluid transfer in an efficient manner having less stringent influent fluid specifications to resist cavitation.
The problem with centrifugal pumps is that they rely upon centrifugal force whereby the influent fluid is directed outward through curved vanes placed upon substantially flat discs toward the outer diameter of the disc providing the pump pressurization. While this pump is resistant to cavitation at low flow rates, the pump is inefficient and may not provide any volume displacement of a fluid. Further, a centrifugal pump that operates on a high fluid viscosity may be impaled by the fluid wherein the pump would duplicate the operation of a mixer.
Despite the type of fluid to be transferred, a common characteristic of fluid is the ability to move fluid through use of two salient properties of fluid, namely, adhesion and viscosity. In such a manner, fluid can be propelled through a medium by reliance upon the skin resistance of a fluid.
A turbine pump developed by Tesla and patented under U.S. Pat. No. 1,061,206 sets forth the accepted embodiment and is incorporated herein by reference. The pump relies upon a plurality of flat rigid discs that are coupled to a shaft and set forth in such a manner that will allow fluid to enter along a center portion of the pump for distribution throughout the plurality of discs. Skin resistance of the fluid operates to engage the side surfaces of the discs wherein rotation thereof causes the fluid to move in correlation with the rotating discs. Unique to these pumps are the ability to transfer gas, a liquid and a solution together or in any combination for the fluids do not touch the pump because the boundary layer created between the surface parts of the disc allow the transfer of fluids that contain corrosive chemicals or even slurry type materials such as sand and dry materials.
Centrifugal force will transfer the fluid outward and when the surface tension is lost, the fluid is directed outward from the pumping chamber. Disc spacing is dependent upon fluid viscosity for optimum efficiency, however, the turbine pump can handle a wide range of viscosities by changing the rotational speed. Larger diameter discs result in a longer spiral path of fluid allowing for use with fluid of greater viscosity. Preferably, the disc spacing is such that the fluid will be accelerated to a near uniform velocity as that of the rotating disc before loss of surface tension.
Another problem with centrifugal pumps is that it is difficult to predetermine general fluid specifications and rational aspects of the pump so as to allow optimum pump efficiency.
As illustrated in FIG. 1 and 2 a prior art turbine pump 100 generally consists of a plurality of flat rigid discs 102 of suitable diameter, keyed to a shaft 104 and held in position by shoulders 106, 108 and an intermediated washer 110. The disc 102 has openings 112 adjacent to the shaft 104 leading to an outer diameter 114. The casing comprises two end casings 116 and 118 which contain the bearings for the shaft 104, stuffing boxes and outlets 120. Fluid would enter the pump into openings 112 as disc 102 rotates in a counter-clockwise manner 124 wherein the fluid enters the spaces 126 between the disc 102 wherein the skin resistance of the fluid requires the fluid to become the same speed as the disc 102 until the fluid gathers sufficient momentum wherein the fluid loses surface tension with the disc 102 and is directed through outlet 120.
A problem with the prior art turbine pumps having spaced apart discs is in specification of the fluid and determination of the rotational aspects so as to match the fluid to the pump for optimum efficiency. Without such matching, the pump becomes inefficient if used with low viscosity fluids or rotated at low speeds. Therefore, what is needed in the art is a turbine pump having a means for accommodating the speed and/or viscosity of fluid so as to provide positive displacement characteristics and optimum efficiency.